i'm making a reverse foot rig in 3ds max ...when i rotate my ankle bone the toe bone gets affected and jerks .....i attached .max file and also uploaded a little video which i recorded to get an idea about the issue .....thanx
It looks like it might be because of the size of your rig. The bones are really very small and 3ds Max needs some room to move. Just resize your rig. But cause you're using a custom bone setup. Make sure you don't scale those bones (I've had a few bad experiences with that) So you might need to re-do the rig but on the bright side, practice makes perfect.
You can check this tutorial for reverse foot setup. there are also several tutorials for creating the entire rig of a character. Check the other chapters.